extend 1 subnet to second router

[hmc250000]

Hi, are there ways to extend a subnet that's configured on one router to another router that's in a different building or site? 

[Philip D'Ath · Accepted solution]

You could run a layer 2 fibre between the two sites.

You could use technology like L2TPv3.

[hmc250000]

Thanks, how do I give you points for your input?

[hmc250000]

Forgot to ask, can this be done with L3 switches (ege 3850s or 3750s?) too? Or would q in q tunneling work to accomplish this? 

[Philip D'Ath]

Most 3750's and 3850's can't do QinQ tunnelling.  You need "Metro Ethernet" swtches to do that.

In your case, it would be easiest to buy a QinQ circuit from a provider.  Then all you have to do is plug it into a normal trunk port and each end, and allow just the VLANs you want to span both sites.

[Joseph W. Doherty]

There sometimes is. Much depends on the feature support of your routers.

[Julio E. Moisa]

As Phillip mentioned you can use L2TPv3 for IP and EoMPLS if you are crossing a MPLS network. But you should verify if it is supported on your routers.